ENVIRONMENT B. O . P Environment B·O·P Operations Report 98/13 January 1999 Bay of Plenty Regional Council Tauranga Harbour Sediment Source Survey Report prepared by Matthew Surman, Design Engineer Richard Clarke, Student - Lincoln University Meredith Carter, Student - Waikato University Environment B·O·P Quay Street P O Box 364 Whakatane NEW ZEALAND ISSN 1173 - 6232 Environment B·O·P Acknowledgements The assistance of other staff – particularly Peter Blackwood, Roger Waugh and Lawrie Donald – in bringing large amounts of information together for this report, is acknowledged. Cover Photo: Erosion site with young and old willows, both with potential for causing further problems. Operations Report 98/13 Tauranga Harbour Sediment Source Survey Environment B·O·P i Executive Summary Environment B·O·P has undertaken a field survey of 23 of the major streams flowing into Tauranga Harbour. The work was undertaken as a component of general investigations of the natural environment of Tauranga Harbour. The work was done predominantly during the university vacations of 1995/6, 1996/7 and 1997/8. The report provides an order of magnitude estimate of sediment transported from stream bank erosion into Tauranga Harbour from the harbour catchments. The report describes and costs possible stream improvement works and estimates the reduction of sediment yields such works may achieve. Operations Report 98/13 Tauranga Harbour Sediment Source Survey Environment B·O·P Contents Executive Summary.............................................................................................. i Chapter 1: Introduction ......................................................................................1 Chapter 2: Background ......................................................................................2 Chapter 3: Waitao Stream .................................................................................4 3.1 Description........................................................................................................4 3.2 History...............................................................................................................5 3.3 Current Situation...............................................................................................5 3.4 Conclusion ......................................................................................................10 Chapter 4: Kaiate Stream (Tributary of Waitao).......................................11 4.1 Current Situation.............................................................................................11 Chapter 5: Kaitemako .......................................................................................13 5.1 Description......................................................................................................13 5.2 History.............................................................................................................13 5.3 Current Situation.............................................................................................13 5.4 Conclusion ......................................................................................................16 Chapter 6: Waiorahi/Waimapu .......................................................................17 6.1 Description......................................................................................................17 6.2 History.............................................................................................................18 6.3 Current Situation – Waiorahi...........................................................................18 6.4 Conclusion – Waiorahi....................................................................................20 6.5 Current Situation – Waimapu..........................................................................20 6.6 Conclusion – Waimapu...................................................................................25 Operations Report 98/13 Tauranga Harbour Sediment Source Survey Environment B·O·P Chapter 7: Kopurererua ...................................................................................26 7.1 Description......................................................................................................26 7.2 History.............................................................................................................26 7.3 Current Situation – Kopurererua Stream from Waikareao Estuary to SH29 Bridge (at 6km). ..............................................................................................26 7.4 Current Situation – Kopurererua Stream Above SH29 Road Bridge...............28 7.5 Conclusion – Kopurererua Stream..................................................................32 Chapter 8: Wairoa River...................................................................................33 8.1 History.............................................................................................................33 8.2 Description......................................................................................................33 8.3 Current Situation – from Ruahihi to Harbour...................................................34 8.4 Conclusion – Wairoa River .............................................................................36 Chapter 9: Omanawa River .............................................................................37 9.1 History.............................................................................................................37 9.2 Current Situation.............................................................................................37 9.3 Conclusion – Omanawa River ........................................................................42 Chapter 10: Ohourere Stream ........................................................................43 10.1 History.............................................................................................................43 10.2 Current Situation – Crawford Road.................................................................43 10.3 Conclusion – Ohourere Stream ......................................................................43 Chapter 11: Te Puna Stream...........................................................................44 11.1 History.............................................................................................................44 11.2 Current Situation – From Odey Road to SH2..................................................44 11.3 Conclusion – Te Puna Stream. .......................................................................48 Chapter 12: Waipapa River .............................................................................49 12.1 History.............................................................................................................49 Operations Report 98/13 Tauranga Harbour Sediment Source Survey Environment B·O·P 12.2 Current Situation.............................................................................................49 12.3 Conclusion – Waipapa River...........................................................................53 Chapter 13: Apata Stream ...............................................................................54 13.1 History.............................................................................................................54 13.2 Current Situation.............................................................................................54 Chapter 14: Wainui River.................................................................................61 14.1 History.............................................................................................................61 14.2 Current Situation.............................................................................................61 14.3 Conclusion – Wainui River..............................................................................64 Chapter 15: Aongatete River ..........................................................................65 15.1 History.............................................................................................................65 15.2 Current Situation.............................................................................................65 15.3 Conclusion – Aongatete River ........................................................................71 Chapter 16: Poupou Stream ...........................................................................72 16.1 History.............................................................................................................72 16.2 Current Situation.............................................................................................72 16.3 Conclusion ......................................................................................................74 Chapter 17: Whatakao Stream .......................................................................75 17.1 Description......................................................................................................75 17.2 History.............................................................................................................75 17.3 Current Situation.............................................................................................75 17.4 Conclusion – Whatakao Stream .....................................................................81 Chapter 18: Waitekohe Stream ......................................................................82